Log Management

The MogDB JDBC driver uses log records to help solve problems when the MogDB JDBC driver is used in applications. MogDB JDBC supports the following log management methods:

Use the connection properties to specify a temporary log file.
Use the SLF4J log framework for interconnecting with applications.
Use the JdkLogger log framework for interconnecting with applications.

SLF4J and JdkLogger are mainstream frameworks for Java application log management in the industry. For details about how to use these frameworks, see the official documents (SLF4J: http://www.slf4j.org/manual.html; JdkLogger: https://docs.oracle.com/javase/8/docs/technotes/guides/logging/overview.html).

Method 1: Use the connection attribute.

Configure loggerLevel and loggerFile in the URL.

This method is easy to configure and applies to the debug driver. However, the log level, file size, and file quantity cannot be controlled. If logs are not manually processed in a timely manner, the disk space will be used up. Therefore, this method is not recommended except for the debug driver.

Example:

public static Connection GetConnection(String username, String passwd){

    String sourceURL = "jdbc:postgresql://10.10.0.13:8000/postgres?loggerLevel=DEBUG&loggerFile=gsjdbc.log";
    Connection conn = null;

    try{
// Create a connection.
        conn = DriverManager.getConnection(sourceURL,username,passwd);
        System.out.println("Connection succeed!");
    }catch (Exception e){
        e.printStackTrace();
        return null;
    }
    return conn;
}

Method 2: Use the SLF4J log framework for interconnecting with applications.

When a connection is set up, logger=Slf4JLogger is configured in the URL.

The SLF4J may be implemented by using Log4j or Log4j2. When the Log4j is used to implement the SLF4J, the following JAR packages need to be added: log4j-*.jar, slf4j-api-*.jar, and slf4j-log4*-*.jar (varies according to versions), and configuration file log4j.properties. If the Log4j2 is used to implement the SLF4J, you need to add the following JAR packages: log4j-api-*.jar, log4j-core-*.jar, log4j-slf4j18-impl-*.jar, and slf4j-api-*-alpha1.jar ( varies according to versions), and configuration file log4j2.xml.

This method supports log management and control. The SLF4J can implement powerful log management and control functions through related configurations in files. This method is recommended.

Example:

public static Connection GetConnection(String username, String passwd){

    String sourceURL = "jdbc:postgresql://10.10.0.13:8000/postgres?logger=Slf4JLogger";
    Connection conn = null;

    try{
// Create a connection.
        conn = DriverManager.getConnection(sourceURL,username,passwd);
        System.out.println("Connection succeed!");
    }catch (Exception e){
        e.printStackTrace();
        return null;
    }
    return conn;
}

The following is an example of the log4j.properties file:

log4j.logger.org.postgresql=ALL, log_gsjdbc

# Default file output configuration
log4j.appender.log_gsjdbc=org.apache.log4j.RollingFileAppender
log4j.appender.log_gsjdbc.Append=true
log4j.appender.log_gsjdbc.File=gsjdbc.log
log4j.appender.log_gsjdbc.Threshold=TRACE
log4j.appender.log_gsjdbc.MaxFileSize=10MB
log4j.appender.log_gsjdbc.MaxBackupIndex=5
log4j.appender.log_gsjdbc.layout=org.apache.log4j.PatternLayout
log4j.appender.log_gsjdbc.layout.ConversionPattern=%d %p %t %c - %m%n
log4j.appender.log_gsjdbc.File.Encoding = UTF-8

The following is an example of the log4j2.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<configuration status="OFF">
    <appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d %p %t %c - %m%n"/>
        </Console>
        <File name="FileTest" fileName="test.log">
            <PatternLayout pattern="%d %p %t %c - %m%n"/>
        </File>
        <!-- JDBC driver log file output configuration. Log rewinding is supported. When the log size exceeds 10 MB, a new file is created. The new file is named in the format of yyyy-mm-dd-file ID. -->
        <RollingFile name="RollingFileJdbc" fileName="gsjdbc.log" filePattern="%d{yyyy-MM-dd}-%i.log">
            <PatternLayout pattern="%d %p %t %c - %m%n"/>
            <Policies>
                <SizeBasedTriggeringPolicy size="10 MB"/>
            </Policies>
        </RollingFile>
    </appenders>
    <loggers>
        <root level="all">
            <appender-ref ref="Console"/>
            <appender-ref ref="FileTest"/>
        </root>
        <!-- JDBC driver logs. The log level is all. All logs can be viewed and exported to the gsjdbc.log file. -->
        <logger name="org.postgresql" level="all" additivity="false">
            <appender-ref ref="RollingFileJdbc"/>
        </logger>
    </loggers>
</configuration>

Method 3: Use the JdkLogger log framework for interconnecting with applications.

The default Java logging framework stores its configurations in a file named logging.properties. Java installs the global configuration file in the folder in the Java installation directory. The logging.properties file can also be created and stored with a single project.

Configuration example of logging.properties:

# Specify the processing program as a file.
handlers= java.util.logging.FileHandler

# Specify the default global log level.
.level= ALL

# Specify the log output control standard.
java.util.logging.FileHandler.level=ALL
java.util.logging.FileHandler.pattern = gsjdbc.log
java.util.logging.FileHandler.limit = 500000
java.util.logging.FileHandler.count = 30
java.util.logging.FileHandler.formatter = java.util.logging.SimpleFormatter
java.util.logging.FileHandler.append=false

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